The ProbSevere algorithm jumped from 36% to 88% between 0052z and 0056z. At 0102z, a large TBSS appeared, so there was certainly lead time on that feature showing up.

Lightning has also increased enough to flag a Significant Thunderstorm Alert. While it didn’t initially look like storm was going produce much, it ended up intensifying – the ProbSevere definitely gave a few extra minutes of lead time.

Jason Williams